I think he's actually strong enough to do that, considering he can hold up a massive crane in his new game.

But in any case, it's just meant to be a sight gag for the trailer (and possibly intro) of that new Spiderman movie. It's like asking why he's blatantly dating MJ in his Spiderman outfit, which would make her a target.

I wouldn't normally question cartoon physics but since people are already debating it..

"Spiderman is totally strong enough to punch a car!"

Irrelevant, this scene is physically impossible.

Imagine a car travelling at highway speeds, going sideways into a pole. What happens to it?

Cars are made of very weak metal, the metal pole just slices straight through the car like a hot knife through butter, or at best the car wraps around the metal pole.

The amount of force required to both stop and send flying backwards a car, applied by an object as small as a fist, would almost certainly result in the object just punching straight through the car like a bullet.

Doesn't matter how strong Spiderman is, at best he could punch a hole through the car, resulting in the rest of the car wrapping around him and sliding down his arm, crashing into his torso, stabbing him with shards of car metal, while the rest of it crashes into MJ and kills her, probably Peter too.

A physics friendly solution would be for Spiderman to create a web net over the window evenly distributing a stopping force across the whole car with the elasticity of his webbing, thus holding the car together.

.. but really who cares it's just a cartoon, and it's obviously meant to be funny.